Hey guys! So I work in a pretty regulated environment with a few VERY old systems, and this is one of them...
I got called into work to look at a Gateway2000 4DX2-66, a system that I think is probably older than me. The system wasn't booting, and it all started with a system battery error message saying that the battery had died. I went up, took a look into it, and expected to just replace the CMOS battery and be done with it, of course it isn't that easy. So I searched the motherboard for a battery slot and found a few spots on the motherboard where it looks like one could have been, but wasn't you can see that in the pictures highlighted by the red boxes. One of these, towards the top says "BT1", and it has a circle that looks to be about the right size, but there's no retention slot to stick a standard CMOS battery, and no sign that there was ever one there. The other signs of a battery are more towards the center of the motherboard and can be seen well in the final picture, they say "Shunt for on-board battery" with an arrow pointing to a solder point, and "External Battery" above a few more solder points.
Now, the other thing I noticed was the large DALLAS DS12887 Real Time chip at the top of the motherboard next to the BT1 marking, I did some research on this chip, and removed it to look into it a bit, and from what I've read slash seen, it seems like this chip has a build in battery, and at the time was a pretty decent clock/calendar with built in RAM and battery chip. From the eBay and other various postings, it looks like this has a regular li-ion battery inside.
I'm 99% sure that my issue is with the battery, as I read from another user on these forums, seen here, as the last post, that this particular computer won't boot from anything besides the A: drive if the battery is dead, and in my BIOS, the only boot option listed in the A: drive.
So my question, after this fairly longwinded post, to all of you, is do any of you have any experience with these DALLAS type chips? Is there a chance that the battery built in to the chip IS in fact the CMOS battery for the entire system, or is it just a sort of time keeping battery? Let me know if you guys need any more information or pictures and I will try to provide them!
Any help is GREATLY appreciated, and here's another link to the imgur gallery of the pictures in case the hyperlink above doesn't work for some reason:
The RTC does in fact have it's cmos battery in the NVRAM block. normally if these go bad you only get the boot off floppy option. They have been used in a lot of the older IBM systems as well. There are two different ways of replacing it. The first is by doing something research and finding a working replacement for it. Or the second would be Taking a small flat head screw driver and taking the top off of it and remove the crystal from it with a soldering iron or desoldering statio. And then resoldering a new one back on. I really wouldn't recommend unless you are very good at soldering.
Alright, that's what I was hoping for, it doesn't look like the chips are too terribly expensive, the department head I was working with ordered a few off of Amazon for like, $10 a piece. Hopefully those will get it crawling along again, we have quite a few people who are decent with soldering and that sort of maintenance in the shops, but if we could spend a little bit of money to get it going again, I think that would be the ideal solution.